Composite structures, such as composite sandwich structures, are often used because of their high strength-to-weight ratio. Such structures are frequently used in the manufacture of aircraft, such as airplanes, helicopters, and the like. Composite sandwich structures typically include an upper skin, a lower skin, and a core adhesively bonded between the upper skin and the lower skin. The upper and lower skins are made of a composite material, such as carbon, graphite, glass fibers, or the like disposed in a polymeric matrix, such as epoxy, polyetheretherketone, or the like. The core often comprises a honeycomb structure made from resin-infused paper. The strength of a conventional sandwich structure is determined by the strength of the core.